Add "Always redirect" checkbox to skip region redirect delay

[Copilot]

Problem

Users redirecting between PostHog Cloud regions (US/EU) must wait 7 seconds on every redirect, even for frequent cross-region users.

Changes

Added an "Always redirect" checkbox that persists user preference in localStorage to skip the countdown:

UI Changes:

• Added LemonCheckbox to redirect modal with label "Always redirect"
• Checkbox state persists across sessions via localStorage.ph_auto_redirect_region

Behavior:

• Unchecked (default): Shows modal with 7-second countdown
• Checked: Redirects immediately, skips modal entirely
• Preference checked on mount in useOnMountEffect

Analytics:

• Redirect to logged-in instance modal shown - fires for both manual (modal shown) and automatic redirects
• When auto-redirecting, event includes auto: true property to distinguish from manual modal displays
• Redirect to logged-in instance always redirect toggled - tracks preference changes

// Check localStorage on mount
const autoRedirectEnabled = localStorage.getItem(AUTO_REDIRECT_KEY) === 'true'
if (autoRedirectEnabled) {
    posthog.capture('Redirect to logged-in instance modal shown', { 
        ..., 
        auto: true 
    })
    window.location.assign(newUrl.href)  // Skip modal
} else {
    setAlwaysRedirect(autoRedirectEnabled)
    setIsOpen(true)  // Show timer modal
    posthog.capture('Redirect to logged-in instance modal shown', { ... })
}

How did you test this code?

• Added unit tests for localStorage read/write (13 tests total, all passing)
• Verified TypeScript compilation and linting
• Existing redirect logic unchanged when checkbox unchecked

Changelog: (features only) Is this feature complete?

Yes

Original prompt

There is a dialog that says:
"You're already logged into PostHog Cloud in the EU region."

This dialog automatically redirects after 5 seconds. Add a checkbox "Always redirect", that stores a local property that allows me to skip waiting for the automatic redirect

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[IchordeDionysos]

@copilot frontend/src/scenes/authentication/RedirectToLoggedInInstance.tsx:110-114
Use the same event with a property "auto": true instead

frontend/src/scenes/authentication/RedirectToLoggedInInstance.tsx:106

[Copilot]

@copilot frontend/src/scenes/authentication/RedirectToLoggedInInstance.tsx:110-114
Use the same event with a property "auto": true instead
...

Changed to use the same event name 'Redirect to logged-in instance modal shown' with property auto: true for automatic redirects. Also moved setAlwaysRedirect to only run when showing the modal (line 118), since it's not needed when auto-redirecting.

Commit: f634f1e